Masaya is a gifted student, working part-time as a tutor. One day, he receives a package. It is a workbook. He frowns as he reads the letter attached to the package. It says, "If you put a woman's name in the workbook, you can control it however you want." At first he takes it as a joke, but decides to give it a try. He inscribes the name of Yumi, his student. As a result, it comes true, and he gets close to her. "This notebook is really capable of it. Now I can have fun with it...."